On the very spot where some of this nation’s first Christians were burned to death for adhering to their beliefs, Pope Francis offered a Mass for hundreds of thousands of Ugandans on Saturday.

He spoke in solemn tones about how “worldly pleasures and earthly power do not bring lasting joy,” and he urged people to “reach out to those in need” and “build a more just society.”

The crowd in front of him seemed to stretch to the horizon. All types of people were there: Catholics and Anglicans, taxi drivers and presidential hopefuls, clergy members, police officers, babies carried on backs and tiny children in tiny suits. Vendors worked through the lines, wads of Ugandan shillings in their hands, doing an excellent business selling clocks, fans, T-shirts and visors – all emblazoned with the pope’s face

The Namugongo shrines, just outside the capital, Kampala, are dedicated to the 19th century Anglican and Catholic converts in Uganda who were burned, speared and tortured by a local king after they refused to renounce their Christian beliefs. The 22 Catholic martyrs were canonized by Pope Paul VI in 1964.

Christianity in Uganda did not just survive. It flourished. Today, about 85 percent of Ugandans are Christian, with Roman Catholics accounting for half that amount. But the Pentecostal church has been growing fast.

Uganda is the middle stop on Francis’ first official trip to Africa. He spent the first part in Kenya, and Sunday he’s scheduled to head to the Central African Republic.

Throughout this trip, the pope has stuck to his signature themes of concern for the poor and the need for greater dialogue between the adherents of different religions. Many Ugandans, though, want the pope to address the need for political and social change. Uganda has been led by President Yoweri Museveni for nearly 30 years, and he is running for re-election next year.

“You know, there’s no good thing about seeing an old man ruling us for so long,” said Jackline Apio, 28, a Protestant and a mother of three. She did not hold out much hope that Francis would broach contentious issues.